The modern trend in the design and implementation of hearing devices is focusing to a large extent on reducing the physical size of the hearing device. Miniaturization of hearing device components is becoming increasingly feasible with rapid technological advances in the fields of power supplies, sound processing electronics and micro-mechanics. The demand for smaller and less conspicuous hearing devices continues to increase as a larger portion of our population ages and faces hearing loss. Those who face hearing loss also encounter the accompanying desire to avoid the stigma and self consciousness associated with this condition. As a result, smaller hearing devices which are cosmetically less visible are increasingly sought after.
Hearing device technology has progressed rapidly in recent years. First generation hearing devices were primarily of the Behind-The-Ear (BTE) type, where an externally mounted device was connected by an acoustic tube to a molded shell placed within the ear. With the advancement of component miniaturization, modern hearing devices rarely use this Behind-The-Ear technique, focusing primarily on one of several forms of an In-The-Canal hearing device. Three main types of In-The-Canal hearing devices are routinely offered by audiologists and physicians. In-The-Ear (ITE) devices rest primarily in the concha of the ear and have the disadvantages of being fairly conspicuous to a bystander and relatively bulky and uncomfortable to wear. Smaller In-The-Canal (ITC) devices fit partially in the concha and partially in the ear canal and are less visible but still leave a substantial portion of the hearing device exposed. Recently, Completely-In-The-Canal (CIC) hearing devices have come into greater use. As the name implicates, these devices fit deep within the ear canal and are essentially hidden from view from the outside.
In addition to the obvious cosmetic advantages these types of in-the-canal devices provide, they also have several performance advantages that larger, externally mounted devices do not offer. Placing the hearing device deep within the ear canal and proximate to the tympanic membrane (ear drum) improves the frequency response of the device, reduces distortion due to jaw extrusion, reduces the occurrence of occlusion effects and improves overall sound fidelity.
While the performance of CIC hearing devices is generally superior to other larger and less sophisticated devices, several challenges remain. When viewed in the transverse plane, the path of the ear canal is extremely irregular, having several sharp bends and curves. This shape and structure, or morphology, varies from person to person. Furthermore, the range and extent of hearing loss typically varies from person to person. A healthy adult ear can sense frequencies between 20 and 20,000 Hz. The same ear can process a sound with an intensity just above 0 dB (a barely audible sound), to a sound intensity over 120 dB. The threshold of pain is 130 dB. Some individuals may only have hearing loss at a certain frequency range and/or within a limited range of sound intensity.
To address the foregoing problems, hearing device manufacturers and audiologists have typically employed programmable hearing devices. In general, programmable hearing devices contain an integrated circuit that maintains customized programs for an individual and/or for a particular sound environment. For instance, the program could direct the hearing device to only amplify sounds at lower frequencies. Alternatively, the program could direct the hearing device to amplify sound frequencies that are only encountered in a specific setting, such as a dinner conversation or a crowded room. Since the range of an individual's hearing loss may change over time, the hearing device program may need to be altered. In order to accommodate these changes, the integrated circuit must be reprogrammed. Reprogramming the integrated circuit is generally performed by using a programming connector that links a programming source (e.g., a computer) with the hearing device circuit. Because an individual's hearing ability may change frequently, or the individual may often move from one sound environment to another, it is desirable that the programming connector allow the integrated circuit to be reprogrammed easily and reliably.
Although known hearing devices employ programming technology, they are not in line with the objectives of component miniaturization. Programmable hearing devices require additional components, such as connection pads, and internal circuitry. These additional components necessarily increase the size of the hearing device. In order to balance the competing objectives of programmability and miniaturization, it is necessary to limit the number and size of the programming components included in the hearing device.
U.S. Pat. No. 4,961,230, entitled "Hearing Aid Programming Interface" ("the '230 patent"), discloses a programming connector that connects an external programming source with internal hearing device circuitry. By fitting inside the battery compartment of a programmable hearing device, the programming connector of the '230 patent obviates the need of a separate port on the hearing device for the programming circuitry. However, the device of the '230 patent still presents problems because it does not provide a structure that allows the electrodes to move independently from the body of the programming connector or independently from one another. Thus, the device of the '230 patent does not provide a consistent or reliable connection between the programming connector, and the internal circuitry of the hearing device.